Signal system.



SIGNAL SYBTEI.

APPLIOA'X'IOI nun) In a. 1900.

928,021. Patented July 13, 1909.

N C re O M 5?- o P1 I L PYZTNE'SSES/ [NS/ENTER I'LJMER I. 231115.52

.UNITED STATES PATENT OFFICE.

ELMER F. BLISS OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY,

A CORPORATION OF NEW YORK.

SIGNAL srs'rmr.

Specification of Letters Patent.

Application filed Kay 6, 1900,. Serial ll'o. 494,201.

clay, and in arranging the signal circuits to permit of its use, a device having a construction similar to that which has been proposed heretofore for use as a rectifier for alternating currents, comprising a winding energized by alternating current, a polarized vibrating member subjected to the action of the alternating current in the Winding and vibrated by it, said member being tuned to a natural period of vibration corresponding to the current in the winding, and contacts actuated by the vibration of said member. Because of the tuning of the vibrating member it is effectively operated only by an alternating current of a certain frequenc My invention will be best understood by reference to the accompanying drawings, in which- Figure 1 shows diagrammatically a block signal system arranged in accordance with my invention; Fig. 2 shows, in elevation, the device which I employ as the track relay; and Fig. 3 shows a modification of circuit connections.

In Fig. 1, A represents the track rails which I have indicated as divided into blocks by insulated joints, as in the usual steam road practice. It will be understood, however, that my invention is ap licable to electric railways having any of t 1e several forms of track circuits heretofore proposed. In such a case the power current may be either direct current or alternating current of a frequency different from that supplied to the signal circuits. B represents t e alternating current generator which supplies the current for the signal circuits through the line wires 6. C represents a transformer having its prima connected to the line wires and its secon ary connected across the track rails. throu h a resistance or impedance 0, serving to limit the flow of current when the transformer secondary is short-circuited by a car. D represents the track rela the construction of which is best-shown in ig. 2. It comprises a winding formed of coils d on a magnetic core having pole 'ieces d d. d is a permanent magnet whic at'its lower end j olns the yoke of the core on which the coils d d are mounted and at its upper end extends in close proximity tothe pole pieces d cl. A magnetic member (1 is supported between the pole pieces d d near the pole of the permanent magnet d and is polarized by that magnet. If alternating current flows through the coils d d the polarit of the ole pieces d d will be reversed wit each a ternation of the current, so that the member (i polarized by the permanent magnet (1 will e attracted first to one pole piece (1 and then to the other. The member (1 is su ported on a flexible strip or fiat spring (1, t e ength of whichis adjusted to ive the member d a natural eriod of vi ration corresponding to the re uency of the alternating current to whic the device is to respond. Contacts (1 d are placed on each side of the spring (1 and are engaged alternately by the s ring when the member d is in vibration. ien current of a frequency other than that on which the device is designed to operate flows through the winding, the vibration of the member (1 which is produced is not sufficient to cause the spring d to engage the contacts (1 As shown in Fig. 1, the spring (1 is connected through the winding of a relay E to the central point on the secondary ofa transformer C. The contacts (1 are connected to the terminals of the secondary winding so that as the member (I vibrates the lower ter-- minal of the winding E is connected alternately tothe terminals of the transformer secondary, but this reversal of connections corresponds to the alternations of the current, so that the relay E is supplied with pulsating direct current. The contacts of relay E control the signal F which is held clear as long as current of the pro r 'frequenc is supplied relay D; that is, so 011g as the b ock is not occupied. A train entering the block, or broken rail, cuts off the current from transformer C, so that the relay D is denergized and the vibration of the member 61 ceases, denergizing relay E, and causin sig nal F to go to stop. Power current or eakage current from any source of a frequency Patented July 13, 1909.

different from that of generator B cannot operate relay D so as to clear the signal.

With the arrangement of Fig. 1 the mechanism of signal F is supplied with alternating current. If it is desired to use direct current mechanism, the arran ement of Fig. 3 may be resorted to, in whic the intermediate relay is omitted and the signal F is controlled directly by relay D. The connections of the mechanism in Fig. 3 are the same as those of relay E in Fig. 1, so that a pulsatin direct current is supplied to the signal mec anism.

I do not desire to limit myself to the particular construction or connections shown and described, but aim in the a pended claims to cover all modifications which are within the scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. In a block signal system, a sourcerof alternating current connected to the track rails, a track relay comprising a winding supplied with current from said source through the track rails and a vibrating polarized ma netic member disposed in the magnetic fieId produced by current in said Winding and tuned to a natural period of vibration corresponding to the frequency of the current normally delivered by said source, and a sig- Igal controlled by the vibration of said mem- 2. In a block signal system, a source of alternating current connected to the track rails, a track relay comprising a winding supplied with current from said source through the track rails and a vibrating polarized magnetic member disposed in the magnetic fie (1 produced by current in said winding and tuned to a natural period of vibration corresponding to the. frequenc of the current normally delivered by sai source, contacts actuated b the vibration of said member, and a signa controlled by said contacts.

3. In a block signal system, a source of alternating current connected to the track rails, a track relay comprising a winding supplied with current from said source through the track rails and a vibrating polarized ma netic member disposed in the magnetic fieId produced by current in said winding and tuned to a natural period of vibration corresponding to the frequency of the current normally delivered by said source, contacts actuated by the vibration of said member, and a circuit including said contacts, signal controlling means, and a source of alternating current of the same frequency as the first-mentioned source, said contacts being connected to rectify the current delivered by said source to said signal controlling means.

4. In a block signal system, a source of al ternating current connected to the track rails, a track relay comprising a winding supplied with current from said source throu h the track rails and a member adapted to %e vibrated by an alternating current in said winding and tuned to a natural period of vibration correspondin to the frequency of the current normally de ivered by said source, and a signal controlled by the vibration of said member.

In witness whereof, I have hereunto set my hand this 5th day of May, 1909.

ELMER F. BLISS.

Witnesses:

BENJAMIN B. HULL, HELEN Onronn. 

